Emma made sandwiches for sale. 50% of the sandwiches were chicken sandwiches and the rest were curry and kaya sandwiches in the ratio 4 : 1. If a customer bought 65% of the chicken sandwiches and all of the kaya sandwiches, what percentage of the curry sandwiches must Emma sell for her to maintain the original percentage of chicken sandwiches at first? Leave your answer in decimals and correct to 1 decimal place.

Chicken sandwiches	Curry sandwiches	Kaya sandwiches
1 u	1 u
	0.8 u	0.2 u

	Chicken sandwiches	Curry sandwiches	Kaya sandwiches	Total sandwiches
Before	1 u	0.8 u	0.2 u	2 u
Change	- 0.65 u	- 0.45 u	- 0.2 u
After	0.35 u	0.35 u	0	0.7 u

50% = ⁵⁰₁₀₀ = ¹₂
65% = ⁶⁵₁₀₀ = ¹³₂₀

Total number of sandwiches = 2 u

Number of curry and kaya sandwiches
= 2 u - 1 u
= 1 u

Number of curry sandwiches at first
= ⁴₅ x 1 u
= 0.8 u

Number of kaya sandwiches at first
= 1 u - 0.8 u
= 0.2 u

Number of chicken sandwiches sold
= 65% x 1 u
= ⁶⁵₁₀₀ x 1 u
= ¹³₂₀ x 1 u
= 0.65 u

Number of kaya sandwiches sold
= ¹₅ x 1 u
= 0.2 u

Number of chicken sandwiches left 
= 1 u - 0.65 u
= 0.35 u

To maintain the percentage of the chicken sandwiches in the end, 
50% → 0.35 u
100% → ^0.35₅₀ x 100 = 0.7 u

Total number of sandwiches in the end to maintain the original percentage of chicken sandwiches = 0.7 u

Number of curry sandwiches left
= 0.7 u - 0.35 u
= 0.35 u

Number of curry sandwiches that Emma must sell to maintain the original percentage of chicken sandwiches
= 0.8 u - 0.35 u
= 0.45 u

Percentage of the curry sandwiches that Emma must sell
= ^0.45_0.8 x 100%
= 56.3%

Answer(s): 56.3%